Electric hand tool with a direction switch for selecting a direction of rotation

Abstract

The invention relates to a power tool with a bidirectional rotary drive (4), comprising a machine housing (1) with a handle section (2) formed therein and a main switch (3) arranged within its reach for switching the rotary drive (4) on and off, as well as a direction switch (5) for selecting the direction of rotation of the rotary drive (4), which is designed as a slide switch that can be actuated on both sides of the machine housing (1) depending on the direction of rotation to be selected, wherein a detent contour (7) comprising at least two switching positions is formed on a central edge region (6) of the direction switch (5), which interacts with spring means arranged on the machine housing (1) that engage therein without play.

Description

[0001] The present invention relates to an electric hand tool with a bidirectional rotary drive, comprising a machine housing with a handle section formed therein and a main switch arranged within its reach for switching the rotary drive on and off, as well as a direction switch for selecting a direction of rotation of the rotary drive, which is designed as a slide switch that can be actuated on both sides of the machine housing depending on the direction of rotation to be selected.

[0002] The application area of ​​the invention extends to handheld power tools, in particular drills, drill drivers, rotary hammers, electric screwdrivers, and the like. With such power tools, the user can usually select the direction of rotation of the rotary drive between clockwise and counterclockwise rotation by means of a manual switch located on the outside of the machine housing. Such a direction switch can be designed as a rotary switch or as a slide switch of interest within the scope of the present invention. State of the art

[0003] The generally known prior art includes slide switches for directional switches on power tools with bidirectional rotary drives. These switches are accessible from both sides of the machine housing and are usually located in a corresponding opening in the handle section of the housing. The directional switch can be pressed either in a first direction to select the first direction of rotation or in the opposite second direction to select the opposite direction. When the directional switch is fully depressed, its actuating surface is usually flush with the surface of the machine housing, which corresponds to the desired switching position.Internally, such a directional switch can be connected to a linear or pivoting gear mechanism to convert the manually mechanically set switching position into the switching position of an electrical switch.

[0004] In practice, such directional switches can be over-pressed, causing them to be pushed deeper into the machine housing than necessary to reach the electrical switching position. This can damage the electrical switch and / or the transmission components. Furthermore, the desired switching position often cannot be reliably set because the switch actuation, in conjunction with the transmission components, has play. Particularly with directional switches that are intended to allow not only the selection of the two directions of rotation in a central switching position but also a neutral position, reliable operation cannot be guaranteed under these circumstances.

[0005] It is therefore the object of the present invention to further improve an electric tool of the generic type in such a way that a correct switching position of the direction switch can be set in a user-friendly manner using simple technical means. Disclosure of the invention

[0006] The problem is solved starting from a power tool according to the preamble of claim 1 in conjunction with its characterizing features. The following dependent claims describe advantageous embodiments of the invention.

[0007] The invention includes the technical teaching that a detent contour comprising at least two switching positions is formed on a central area of ​​a direction switch designed as a slide switch, which interacts with spring means arranged on the machine housing that engage without play.

[0008] The at least two switching positions correspond to switching between clockwise and counterclockwise rotation of the rotary drive, also referred to as left-hand and right-hand rotation, respectively. A third switching position can be provided for a neutral position in which the rotary drive is stationary, for example, for the chiseling function of a rotary hammer. The middle position may also be configured as a transport lock position in which the main switch cannot be operated and the power tool therefore cannot be switched on.

[0009] The spring elements according to the invention exert a permanent spring pressure on the detent contour, so that the distance between adjacent switching positions and the actuating force can be easily adjusted by means of its shape. For such a detented switching function, the central edge region of a generic directional switch is preferably used, which is located in the section between the actuating surfaces on both sides within the machine housing. Since a directional switch according to the invention is preferably designed to be flat, the detent contour can be optimally arranged on its edge region; preferably, the edge region facing the tool is suitable for this purpose.

[0010] According to a preferred embodiment of the invention, the spring elements on the machine housing side consist of a spring tongue molded into the handle section of the machine housing, which extends outwards and has a preferably rounded cam section at its distal end. This cam section bears resiliently against the detent contour of the direction switch. For backlash-free interaction, the detent contour can have the same curvature as the cam section of the spring tongue engaging therein, which also contributes to a precise switching feel. Preferably, the detent contour is wave-shaped, with each trough forming a switching position. However, it is also conceivable that the detent contour is triangular to enable backlash-free engagement. Due to the preferably direct molding of the spring tongue onto the machine housing, the spring elements can be manufactured in a simple manner by injection molding.However, it is also conceivable that separate components made of spring steel or elastomer elements are used as spring elements.

[0011] Preferably, the spring elements acting on the detent contour are pre-tensioned. In the case of a spring tongue, this can be easily and functionally integrated by a guide rib acting opposite the direction switch and integrally molded onto the machine housing. Additionally, it is conceivable to integrally mold further guide ribs surrounding the direction switch at parallel intervals, each of which provides longitudinal guidance of the direction switch within the continuous housing recess to ensure jam-free operation even under high dust conditions.

[0012] According to a further improvement of the invention, the direction switch has an arrow marking or the like on its upper surface to visualize the selected switching position. This marking is visible through a window opening in the handle section of the machine housing. The window opening is preferably located on the top of the machine housing near the handle section to ensure ergonomic handling.

[0013] Preferably, the arrow marking of the direction switch comprises a forward-pointing arrow indicating a clockwise direction of rotation and a parallel, rearward-pointing arrow indicating a counterclockwise direction of rotation. The forward-pointing arrow points towards the tool, while the rearward-pointing arrow points towards the operator. The selected switch position can be clearly read by masking the window opening. The size of the window opening depends on the geometry of the detent contour, specifically its wavelength.

[0014] As part of such a switch position indicator, it is also possible to make the area between the two arrows visible in the window opening to indicate a neutral position of the direction switch. In this case, the arrows can either no longer be visible or at least only be partially visible in the window opening at the edge. This gives the operator a clear indication that a neutral position is selected. Alternatively, it is also conceivable to mark the neutral position with a separate symbol, for example, an "N," located in the area between the two arrows. However, the variant with the arrows only partially visible in the window opening offers the advantage of short switching strokes. This very compact design is possible because the direction switch according to the invention can be operated virtually without backlash, which is a prerequisite for a correspondingly precise indication.

[0015] According to a further improvement of the invention, it is proposed that the direction switch has a shoulder on both sides adjacent to the detent contour, which interacts with a stop structure projecting centrally on the machine housing side to form end stops on both sides. The two shoulders preferably form a recess on the edge of the low-profile direction switch, from which the centrally arranged detent contour protrudes. Such a contour can also be easily produced by injection molding in a direction switch made of plastic. The shoulders on both sides prevent the direction switch from being over-pressed and thus also prevent damage to the subsequent electrical switch in the chain of action.In power tools with an integrated bearing block and integrated vibration compensation, the protruding stop structure on the machine housing side can also be used to lock such a bearing block by providing corresponding undercuts or the like.

[0016] According to a preferred embodiment of the invention, it is proposed that the directional switch, designed as a slide switch, be arranged on the outside of the handle section such that it can be actuated in one direction with at least the thumb of one hand when the handle section is gripped. In connection with this, the main switch, located adjacent to the directional switch, can be designed as a two-finger switch and arranged on the inside of the handle section such that it can be actuated with at least the index and / or middle finger of one hand when the handle section is gripped. Detailed description based on drawing

[0017] Further measures improving the invention are described in more detail below, together with a description of a preferred embodiment of the invention, with reference to the figures. The figures show: Fig. 1 a schematic side view of a power tool with a direction switch arranged on the handle section for selecting the direction of rotation of the rotary drive, Fig. 2 a partial longitudinal section through the machine housing in the area of ​​the handle section, Fig. 3 a detail view in the area of ​​the detent contour of the direction switch, Fig. 4 a graphic representation of the switching positions of the direction switch effected by the detent contour, Figs. 5a to 5c a sequence of top views of the optical display of the different switching positions, and Fig. 6 a side view of the machine housing in the area of ​​a direction switch inserted therein.

[0018] According to Fig. 1The power tool, designed here as a rotary hammer, consists of a machine housing 1 with a handle section 2 attached to it, within the reach of which a main switch 3 is provided for switching on and off a rotary drive 4 integrated into the machine housing 1. A direction switch 5 arranged adjacent to this in the area of ​​the handle section 2 serves to select the direction of rotation of the rotary drive 4. The direction switch 5 is designed as a slide switch that can be actuated from either side of the machine housing 1, depending on the selected direction of rotation.

[0019] The directional switch 5, designed as a slide switch, is arranged on the outside of the handle section 2 on the machine housing 1 such that it can be actuated in one direction at least with the thumb of one hand when the handle section 2 is gripped. The main switch 3, arranged adjacent to it, is designed as a two-finger switch and is positioned on the inside of the handle section 2 such that it can be actuated, preferably with the index and middle fingers of one hand, when the handle section 2 is gripped.

[0020] According to Fig. 2 A detent contour 7, comprising several switching positions, is formed on a central edge region 6 of the direction switch 5. The detent contour 7 of the direction switch 5 interacts with spring elements formed on the machine housing 1, which in this embodiment consist of an injection-molded spring tongue 8 extending outwards.

[0021] Furthermore, the direction switch 5 has a shoulder 12a, 12b on both sides adjacent to the detent contour 7, which interacts with a stop structure 13 projecting centrally on the machine housing side to form end stops 13a, 13b on both sides. The shoulders 12a and 12b thus limit the insertion depth of the direction switch 5. A stop 13a of the stop structure 13 is designed to interact with the shoulder 12a, and a stop 13b of the stop structure 13 is designed to interact with the shoulder 12b. In this embodiment, the stop structure 13 also serves to secure a bearing block 9.

[0022] According to Fig. 3 The detent contour 7 of the direction switch 5 is wave-shaped, with each of its wave troughs 10a to 10c forming a switching position. A rounded cam section 11, arranged at the distal end of the spring tongue 8, engages in this position.

[0023] After Fig. 4The detent contour 7, extending along two wavelengths λ, provides a total of three switching positions. Each wavelength λ corresponds to the distance between the switching positions. The first switching position I on the left corresponds to a clockwise direction of rotation. The middle switching position II corresponds to a neutral position in which the rotary drive is inactive, and the third switching position III corresponds to a counterclockwise direction of rotation.

[0024] As from Fig. 5a As can be seen, the direction switch 5 has an arrow marking on its upper side to indicate the direction, which is visible through a window opening 15 in the handle section 2 of the machine housing (not shown here). The arrow marking shows a forward-pointing arrow 14 to indicate a clockwise direction of rotation.

[0025] According to Fig. 5bA backward-pointing arrow 14' is provided to indicate a counterclockwise direction of rotation, which appears in the other switching position of the direction switch 5.

[0026] Furthermore, according to Fig. 5c The indication of a neutral position of the direction switch 5 is provided by making the area between the two arrows 14 and 14' visible in the window opening 15. The two arrows 14 and 14' are only partially visible for this optical indication.

[0027] According to Fig. 6 The direction switch 5, designed as a slide switch, is arranged within a continuous housing recess 16 in the handle section 2 of the machine housing (not shown here) and is guided in the direction of actuation by guide ribs 17a to 17g. The guide rib 17d serves to apply a preload to the spring tongue 8 acting on the opposite side of the direction switch 5.

[0028] The invention is not limited to the preferred embodiment described above. Rather, variations thereof are also conceivable and are included within the scope of protection of the following claims. For example, it is also possible to design the spring elements as separate spring components. Furthermore, the detent contour can also be designed with a different geometry, for example, corresponding to a triangular curve. Reference symbol list

[0029] 1 Machine housing 2 Handle section 3 Main switch 4 Rotary drive 5 Direction switch 6 Edge area 7 Detent contour 8 Spring tongue 9 Bearing block 10 Shaft trough area 11 Cam section 12 Edge shoulder 13 Stop structure 14 Arrow 15 Window opening 16 Housing mount 17 Guide rib

Claims

1. Power tool with a bidirectional rotary drive (4), comprising a machine housing (1) with a handle section (2) formed therein and a main switch (3) arranged within its reach for switching the rotary drive (4) on and off, as well as a direction switch (5) for selecting the direction of rotation of the rotary drive (4), which is designed as a slide switch that can be operated on both sides of the machine housing (1) depending on the direction of rotation to be selected, characterized by the fact that A detent contour (7) comprising at least two switching positions is formed on a central edge area (6) of the direction switch (5), which interacts with spring means arranged on the machine housing (1) that engage without play.

2. Power tool according to claim 1, characterized by the fact thatThe spring means on the machine housing side consist of a spring tongue (8) molded into the handle section (2) of the machine housing (1), which extends outwards and has a rounded cam section (11) at its distal end, which springs against the detent contour (7) of the direction switch (5).

3. Power tool according to claim 2, characterized by the fact that the spring tongue (8) is pre-tensioned by a guide rib (17d) arranged opposite the direction switch (5) and formed on the machine housing (1), wherein further guide ribs (17a - 17g) surrounding the direction switch (5) at parallel intervals ensure longitudinal guidance of the direction switch (5) within a continuous housing recess (16).

4. Power tool according to one of the preceding claims, characterized by the fact that the detent contour (7) is wavy, the trough areas of which (10a - 10c) each form a switching position.

5. Power tool according to one of the preceding claims, characterized by the fact that the direction switch (5) has at least one upper arrow marking for direction indication, which is visible through a window opening (15) in the handle section (2) of the machine housing (1).

6. Power tool according to claim 5, characterized by the fact that The arrow marking includes a forward-facing arrow (14) to indicate a clockwise direction of rotation and a rearward-facing arrow (14`) arranged parallel to it to indicate a counterclockwise direction of rotation.

7. Power tool according to claim 5, characterized by the fact that To indicate a middle neutral position of the direction switch (5), the area between the two arrows (14, 14`) is visible in the window opening (15).

8. Power tool according to one of the preceding claims, characterized by the fact thatthe direction switch (5) has a marginal step (12a, 12b) on both sides adjacent to the detent contour (7), which cooperate with a stop structure (13) projecting centrally on the machine housing side to form end stops on both sides.

9. Power tool according to one of the preceding claims, characterized by the fact that The direction switch (5), designed as a slide switch, is arranged on the outside of the handle section (2) in such a way that it can be actuated in one direction with at least the thumb of one hand when the handle section (2) is gripped.

10. Power tool according to one of the preceding claims, characterized by the fact that the main switch (3) arranged adjacent to the direction switch (5) is designed as a two-finger switch and is arranged inside the handle section (2) in such a way that it can be operated with at least the index and / or middle finger of one hand when the handle section (2) is gripped.

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